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Open Source and information security mailing list archives
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Date: Sat, 26 Jul 2008 14:35:39 -0400 From: "H. Peter Anvin" <hpa@...or.com> To: Andi Kleen <andi@...stfloor.org> CC: Ingo Molnar <mingo@...e.hu>, "Luis R. Rodriguez" <mcgrof@...il.com>, linux kernel <linux-kernel@...r.kernel.org>, "H. Peter Anvin" <hpa@...nel.org>, Ivan Seskar <Seskar@...lab.rutgers.edu>, jfm3 <jfm3@...lab.rutgers.edu>, Sujith <m.sujith@...il.com> Subject: Re: Bug on 2.6.26 - x86 VIA Nehemiah CentaurHauls processor cannot boot Andi Kleen wrote: > > This was originally supposed to be handled in the early real mode > head.S code. That is why I put the CPUID checking code in there > to error out early when you can still print to the console > using the BIOS functions. > > I suspect this regressed when that code was moved to C, because > now the C compiler generates CMOV early. > > How about always building the real mode C code with -march=i386? > It is not performance critical so that is ok. > The real mode code *is* compiled with -march=i386, and in the CMOV case it will err out with a legible message. The issue isn't CMOV at all, it's with long NOPs, which don't have a CPUID bit -- they're supposed to be supported if family >= 6, but some VIA chips violate that condition. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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